The present invention relates to a medical imaging apparatus, particularly to a medical imaging apparatus capable of providing both an X-ray image and a magnetic resonance tomogram approximately at the same time.
Improved performance of diagnostic imaging apparatuses and of catheters and guiding wires has made available interventional radiology (referred to as IVR hereinafter), in which a catheter equipped with various instruments on its tip is inserted into a human body under X-ray fluoroscopy. This has enabled diagnosis and therapy of lesions to be conducted simultaneously. As a diagnostic apparatus for conducting IVR, an X-ray diagnosis apparatus of bi-plane system has been employed, which, as shown in FIG. 8, has two X ray tube and image intensifier (referred to as I.I. hereinafter) pairs supported face to face by a tube stand.
By using this X-ray diagnosis apparatus, images can be obtained from two directions simultaneously. However, these images can not provide three dimensional information regarding to the relationship between the tip of a catheter and a lesion since each of the images is a two dimensional fluoroscopic image. In addition, internal organs can not be observed in the two dimensional images because of their low X-ray absorptance. Therefore, it is hard to grasp the position of the catheter in regard to the organs.
On the other hand, an X-ray CT is known to be suitable for grasping the relative position of the organs and the catheter or the like. However, it can not be applied to the patient together with the X-ray diagnosis apparatus having a tube stand since the X-ray CT requires a scanner part which hampers the simultaneous application with the X-ray CT. Accordingly, when X-ray CT images are required during the application of X-ray fluoroscopy, the patient must be moved to the X-ray CT in order to take the CT image and confirm the relative position of the catheter and the organ. Then the patient has to be returned to the X-ray fluoroscopic apparatus to advance the catheter or collect tissue. However, it is dangerous and not desirable to move the patient with the catheter inserted.
There is another problem that the relative positions in the two images, i.e. the CT image and the fluoroscopic image, may be inconsistent since locomotion of the patient between the X-ray CT and the X-ray fluoroscopy takes at least several tens of seconds. For example, even though one apparatus is applied as the patient holds his breath, the same condition can not always be reproduced in the other apparatus. A slight time lag may produce change of the position of the organ and this change may make a precise diagnosis difficult.